5'-Amino-Modifier C12-PDA


Product Specifications

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Our more recent 5'-amino modifiers, protected by a novel phthalic acid diamide (PDA) protecting group, are stable solids. In contrast to the TFA protected amino modifiers, which are viscous oils, the analogous PDA protected compounds are granular powders. This important property of these compounds allows straightforward handling, storage and aliquoting and leads to a significant increase in stability.

Deprotection with methylamine in gas phase or aqueous solution or AMA leads to fast and complete removal of the PDA protecting group. However, ammonium hydroxide will not drive the equilibrium reaction to completion and only partial deprotection occurs - overnight deprotection with ammonium hydroxide will yield around 80% active amine.

We offer three PDA Amino-Modifiers:

  • Amino-Modifier C6-PDA (10-1047)
  • Hydrophobic 5'-Amino-Modifier C12-PDA (10-1948)
  • Hydrophilic 5'-Amino-Modifier-TEG-PDA (10-1949)



  • Coupling: No changes needed from standard method recommended by synthesizer manufacturer.
  • Deprotection: Synthesize using acetyl-protected dC (10-1015-xx) and deprotect in 30% Ammonium Hydroxide/40% Methylamine 1:1 (AMA) at 65°C for 10 minutes. Removal of the PDA requires 30 minutes at Room Temperature with AMA.
Diluent 25% DCM in Acetonitrile
Storage Freezer storage, -10 to -30°C, dry
Stability 1-2 days

Intellectual Property

PDA amino-modifiers were developed by Stefan Pitsch and ReseaChem GmbH (S. Berger), Patent pending.

Dilution/Coupling Data

The table below show pack size data and, for solutions, dilution and approximate coupling based on normal priming procedures.

ABI 392/394

Catalog # Pack Size Grams/Pack 0.1M Dil. (mL) Approximate Number of Additions
LV40 LV200 40nm 0.2μm 1μm 10μm
10-1948-02 0.25 g .25grams 4.44 134.67 80.8 50.5 36.73 26.93 6.73
10-1948-90 100 µmol .056grams 1 20 12 7.5 5.45 4 1


Catalog # Pack Size Grams/Pack Dilution (mL) Approximate Number of Additions
Molarity 50nm 0.2μm 1μm 15μm
10-1948-02 0.25 g .25grams 6.63 0.07 126.2 78.88 57.36 7.89
10-1948-90 100 µmol .056grams 1.5 0.07 23.6 14.75 10.73 1.48